Former Buffalo Bills quarterback Jim Kelly is dealing with an aggressive, spreading recurrence of cancer, his wife wrote on Instagram, and his health is deteriorating, multiple media outlets reported Monday.

Jill Kelly wrote that Jim Kelly was tentatively due to undergo surgery in Manhattan on Thursday. According to Buffalo News 4, Jim Kelly has been in and out of hospitals the past 10 days.

Late last week, former teammates Thurman Thomas, Bruce Smith and Andre Reed visited Kelly at his home.

The Hall of Famer was diagnosed with upper jaw cancer last June, and he had surgery to remove part of his jawbone. He subsequently was declared cancer-free without undergoing radiation or chemotherapy.

However, on March 14, the Erie County Medical Center announced that Kelly's cancer had reappeared.

“Jim Kelly came to ECMC this week for continued testing related to his oral surgery,” said Dr. Thom Loree, a head and neck surgeon, in a statement. “Unfortunately, it has been determined that his cancer has returned.

"Our team of head and neck cancer specialists is determining a course of treatment that will allow Mr. Kelly to battle this cancer successfully. Mr. Kelly has asked that you to keep him and his family in your thoughts and prayers."

Kelly, 54, entered the Pro Football Hall of Fame in 2001 after playing from the Bills from 1986 to 1996. He holds most of the franchise's passing records.

The Kellys' son, Hunter, was born with Krabbe disease, a hereditary genetic disorder. Given little more than three years to live, Hunter died at the age of 8 in 2005.

The couple's daughter, Erin, a college student, on Saturday posted a photo showing her lying next to her father in a hospital bed, her head resting on his right shoulder.

“Watching the Syracuse game with daddy … he's my buddy! Love him so much!!” Erin's tweeted.

Fellow Hall of Fame quarterback John Elway, the Denver Broncos' executive vice president, was among those who tweeted support for Kelly:

“My thoughts and prayers go out to Jim Kelly and his family! There's not a stronger or tougher guy to handle this battle!!”